1. Field of the Invention
This invention pertains to two-piece buttons having coplanar shell flanges, and also to apparatus for manufacturing such buttons.
2. Description of the Prior Art
The word “button” traditionally has included three different types of items: upholstery buttons, apparel buttons, and novelty buttons. The present invention is directed only to novelty buttons, and the word “buttons” as used herein means novelty buttons.
Buttons and machines for manufacturing them are well known and have been in widespread use for many years. Buttons are commercially available in numerous sizes and in several shapes such as round, rectangular, and oval. Buttons may be of one-piece or two-piece construction. In a one-piece button, a flexible graphic is overlaid on a shell. The edge of the graphic is captured between the main portion of a shell wall and a margin of the shell wall that is bent outward and upward to hold the edge or the graphic. A wide variety of one-piece buttons are marketed under the trademark LarLuLine.
Two-piece buttons are generally considered to be of superior quality to one-piece buttons. Referring to FIGS. 1–3, a two-piece button 1 is made from a flat back 39. The flat back button 1 also has a shell 3 and a flexible laminate 7. The laminate 7 typically consists of a sheet of a pre-printed graphic 9 covered by a protective film 11 of transparent polyester or similar material. The laminate is overlaid on the dome 13 of the shell 3. At an intermediate step in the process of manufacturing the button 1, a skirt 15 of the laminate overhangs the free edge 17 of an annular wall 19 of the shell.
The flat back 39 has a periphery 41. The skirt 15 of the laminate 7 is tucked around the shell wall free edge 17 and around the flat back periphery 41. Then the shell wall 19 is crimped to become frusto-conical in shape as shown at reference numeral 19A and to capture the laminate between the shell 3 and the flat back. My prior machines as disclosed in U.S. Pat. Nos. 6,038,944 and 6,393,686 are capable of efficiently manufacturing the flat back buttons 1.
Turning to FIGS. 4 and 5, a round flat back button 59 is made from a shell 63 with an annular wall 64 that terminates in a free edge 69. The flat back button 59 further has a flat back 65 with a periphery 68, and a flexible laminate 67. The shell annular wall 64 has a margin 61 adjacent the free edge 69. In the flat back button 59, the shell margin 61 is bent over at 180 degrees to create a round ring-like flange 71. A skirt 66 of the flexible laminate 67 is tucked between the flange 71 of the shell wall 64 and the flat back 65, and around the flat back periphery 68. It is thus seen that the button flange 71 lies in a single flat plane 72 parallel to the flat back 65.
The round button 59 with the coplanar flange 71 is sometimes referred to as a button medallion. That term is used, for instance, in my prior U.S. Pat. Nos. 6,038,944 and 6,393,686 to identify the button 59. Those patents also describe in detail a manual machine and methods for manufacturing round buttons 59 with the coplanar flanges 71. Specifically, my two prior patents disclose a manual machine in which a ram cooperates with a pickup die and a crimp die in a three-stroke process to manufacture the buttons 59 with the coplanar flanges 71. That is, it was necessary to press the button 1 a third time to complete the coplanar button 59.
Buttons with flat backs are not limited to being round in shape. Looking at FIG. 6, the components of a prior rectangular flat back button 43 are shown. The rectangular flat back button 43 has a shell 45, flexible laminate 47, and flat back 49. As illustrated, the flat back 49 is flat for its entire area. However, a back may have margins 51 that are very slightly bent out of plane and still be considered to be a flat back. The flat back may be made of metal or plastic material. The assembled rectangular flat back button is shown in FIG. 7. In the completed rectangular flat back button 43, the four margins 51 of the shell 45 have been crimped, as shown at reference numeral 51A, to make an acute angle with the shell center portion 53. The skirt 55 of the laminate 47 is tucked around the four free edges 56 of the shell and between the four crimped shell margins 51A and the periphery 57 of the flat back 49.
Because of the angular margins 51A, the prior rectangular buttons 43 did not have a finished appearance. In addition, normal processing tolerances sometimes allowed the angular shell margins 51A to inadequately secure the back and graphic to the shell. As a result, the buttons had a tendency to come apart during handling and usage. The angular margins were also prone to snag on clothing and other objects. Some prior rectangular buttons had margins that were more closely parallel to the flat back 49 than is shown in FIG. 7. Nevertheless, while the round buttons 1 with the flat back 39 and frusto-conical shell wall 19A have been accepted by consumers, the prior rectangular buttons 43 with the angular shell walls 51A have not.
To achieve a secure assembly of rectangular buttons with straight line elements instead of angled margins, it is necessary to fully form the flanges into a coplanar configuration. When a round button 1 or rectangular button 43 is further processed to form buttons with flanges that are coplanar and parallel with the flat backs 39 and 49, respectively, a secure assembly is created that engages its ultimate use more desirably. That is, it is more readily adhered to a surface such as a plaque by adhesive or attached to a refrigerator or file cabinet by means of a magnet or simply worn on a garment by means of a safety pin.
A prior rectangular button 73 with coplanar shell flanges is shown in FIGS. 8–10. The button 73 has a shell 75, which is preferably made of sheet metal approximately 0.008 to 0.009 inches thick. The shell 75 has four free edges 77 and clipped corners 78. There is a margin 79 of metal along each of the free edges 77. The button 73 further comprises a rectangular flat back 81 with a periphery 83, and a flexible laminate 85. The laminate 85 is composed of a graphic 87 overlaid with a film 89 of transparent and protective material, such as polyester film. The button 73 is characterized by the fact that the shell margins 79 are bent to have flanges 91 that all lie in a single flat plane 93.
Although my prior manual machines for manufacturing round buttons have met with success, it is desirable to make them even more productive, such as by reducing the number of strokes required to manufacture a button.
Thus, it is desirable to both increase the productivity of button making machines and to increase the variety of readily available buttons.